Bridge.



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BRIDGE. v 7 APPLICATION FILED JULY 5', 1913 Patented Apr. 14', 19M

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- I WWW/Z092 G. "E. ,PAINIEL BRIDGE.

APPLICATION FILED JULY 5, 1918 Patentd 14, 1914;

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omrroran n. time, or Camila. tirimorsyhsiiibrp or onn-roun rn To LUTHERr JOHNS, or onxcaco, ILLINOIS.

BRIDGE.

oeaeoe.

Spec ilication of Letters i'atent. App 14,1914,

Application filed July 5, i913. Serial No. 777,509.

To all whom it may concern.

"Be it known that I, CLIFFORD E. PAINE, a

citizen of the United States, residing at Chi cago, in the county ofCook-and State of Illinois, have invented certain new and usefulImprovements in Bridges, of which the following is a specification.

My invention relates to bridges, and has more particular referencetobridges of the lift type in which a span or portion of the bridge israised. I

It is not broadly new .to provide lift bridges in whicha system oflevers and weights is employed for counterbalancing the span or aportion thereof when the same is being raised or lowered. Variousobjectioiis exist in the counterbalancing means heretofore suggested,however, as for instance the inclusion therewith of a plurality ofcounterbalancing weights in each device and the necessity for shiftingat least one of such weights in order to compensate for thearcu'al'swing of the lifting or counterbalancing lever pivoted on afixed, support. Other objections are the large number of pivotalconnections employed, all producing friction and wear and entailinglarge expense in the repair ofbroken 'or worn out parts as well as inthe initial costs. Still other notable obj ectio'nsare necessitiesfor'long link connections for shifting the counterweight, which linksowing to their great length,

must be made obj ectionably heavy and sometimes be well braced, thusadding greatly to the cost as well as to the objection of and amultiplicity of parts. Furtlier objections v ar-e to the appearance of-3 hitherto suggested structures, andalso to the diiricnlties experiencedin the construction. and arrangement of details to avoid the in-.terferen'oe of operative parts. i

The principal objects of the present invention are to provide .acounterbalance I for like in which the weight of I the counterbalancingmechanism :as well as bridges and the the load to be lifted may becounterbalanced by 3 Single counterweight; further to provlde suchapparatus in which such balance is maintained in all operative positionsof the arts, and notably withoutit e necessity of s ifting acounterweight relative to its supportingmember.

A-further object is toprovide a counterbala'noing system of levers, etc.by which when 'thebridge ismoved vertically the counterweight as a wholealso moves vertically or approximately verticall throughout 1ts entiretravel, as distinguished from other proposed devices in which a singleweight or one of a pluralityof the weights used moves in a curved pathof travel.

Further objects are to provide a countel-balancing system which issimple of construction, of comparatively few parts, havmg few pivotalconnections, which may be made in accordance with the principles of goodengineering, and one whichdoes not require the inclusion of poorstructural details in order to avoid interference of rel- I ativelymoving parts; to provide a counterbalancing system in which thecounterweight may be fixed to or upon its supporting memher, or may besuspended as a pendant therefrom, all without prejudice to the perfectbalance of the structure in all operative positions of the same.

' General objects are to provide a-counterbalancing system and a bridgehaving a counterbalancing device or devices in which thecounterbalancing structure is of simple and economical design,manufacture and re pair, which is strong and durable, effective inoperation, and which is pleasing in outline and general appearance.

In the drawings which accompany and form a part of this application Ihave illustrated certain preferred and modified embodiments of myimprovements as applied to a bridge of the vertical lift type, the

parts being shown diagrammatically in a mannerfivell suited to a clearunderstanding of the inventron herein set forth.

In these drawings Figure 1 is a side elevation got a bridge showing thepreferred form of "counterbalancing apparatus adjacent to eaclrendthereof, the vertically movable span being shown in lowered position;Fig. '2 is .a similar view to that of Fig. 1, but showing the'spanraised; Fig. 3 is a top plan showing a pair of counterbalance le- -versadjacent to each end of the movable span, each pair carrying a singlecounterweight; Fig. 4 is a side view showing a modified application inwhich. the span and counterweight are in reverse arrangement from thatshown in Fig. 1; Fig. 5 is an en larged diagrammatic side elevation ofone (lit the counter-balancing devices shown in ig. l.

Referring to Fig. 1 the vertically movable span 20 is shown as restingon piers 21 which also support the towers or fixed supports 22 adjacentto the ends of the movable span and which supports are provided at theirupper ends respectively with a trunnion bearing for a trunnion 30. It isunderstood that bridges of this type usually have four counterbalancing.devices-a pair at either end of the movable span'as indicated in Fig. 3.The counter-balancing devices respectively may conveniently be connectedto the span 20 at a point 25 on the truss 24, although the connectionsmay be made at other suitable points. Upon the support 22 there may bearranged a toothed rack 26 extending from the bottom to substantiallythe highest point thereof, and on the bridge span 20 I haveconventionally illustrated means forraising and lowering the span,comprising the toothed wheels or pinions 27 adapted to engage the teethof the racks 26, the pinions being rotatable by means of the shaft 28extending from one end of the bridge to the other and itself suitablyrotated by driving mechanism 29, a similar shaft, pinions, etc. beingpositioned on the opposite side of the span, the two driving shaftsbeing adapted by means of the cross shaft 28 (Fig. 3) to raise or lowerthe four corners of the span simultaneously and with equal movement. Thespan may be suitably guided in its vertical movements by sliding orrolling connections in engagement with the fixed supports, the supports22 (see Fig. 5) being shown as provided with guides 22 adapted to beengaged by the shoe 20 on the span 20.

In the preferred arrangement illustrated a link 31 is pivotally mountedon the trunnion 30, which link at its upper end is pivoted at 32 to thecounterbalance lever 33 which, as shown, extends on either side of thepivotal connection 32. The lever 33 may suitably be in the form of atruss as illustrated in the drawings. A connecting lever 34 is pivotallyattached to one end of the lever 33, as at 35, the other end of thelever 34 being pivotally connected to the truss 24 by the pin 25. A link36 is pivoted upon the main trunnion 30 and is also pivotally connectedto the lever 34 at a point 37 the samedistance from the center of thepivotal point 35 as the center of the pivot 32 is spaced from the centerof the trunnion 30, the distance between the points 30 and 37 beingthesame as that between the points 32 and 35.

It will be noted that the arrangement of the parts hcrcinabove describedis such that lines joining the pivotal centers 30, 32-, 35 and 37 formaparallelogram. If the line 3532 is produced it will intersect a lineproduced through points 2530 at a point as 4-1. It is a property of thisarrangement that the three points 41, 30 and 25 will alcally,horizontally, or with a combination ways remain in a straight line inall operative positions of the device. If the links 31 and 36 and thelevers 33 and 34 were themselves without weight a counterweight fixedupon lever 33 with its center of gravity at the point 41 and being of aweight sufficient to balance a constant weight applied at the point 25would perfectly balance such weight in all of the operative positions,and this whether the point 25 be moved vertiof movements vertical andhorizontal. Ow-

ing, however, to the weight of the links and levers mentioned additionalcounterweight must be added to counterbalance these parts. i The weightand-location of the counterweight may be practically determinedaccording to methods well understood in the art. For the purposes ofthis description, we will assume that a weight W is applied at the point25. For center of gravity calculations we may consider a proper portionof the weight of link 31 as concentrated at the point 32 and the remainder as concentrated atthe fixed point 30. Likewise a portion of theweight of link 36 may be considered as concentrated M37 and theremainder at the fixed point 30. A part of said portion considered asconcentrated at 37 may now be considered as concentrated at 35 and theremainder at 25. A proper portion of the weight of member 34 isconsidered as concentrated at 35 and the remainder at 25. The weight ofthe counterbalance lever 33 is concentrated at the center of gravity ofsaid lever, assumed for the purpose 'of this description as at point 43.Summarizing we have the weight of the various members of the deviceproperly proportioned to the points of con centration 30, 32,35, 25 and43. The part considered concentrated at 30. obviously does not requireto be counterbalanced. The portion considered as concentrated at 25 maybe added to the weight I and considered as additional weight at 25 to becounterbalanced. The remainder of the weight of the links and leversmentioned is now concentrated, as hereinabove shown, at the points 32,35 and 43,1111 bearing a fixed relation to the counterbalance lever Thecenter of gravity of the weights concentrated at points 32, 35 and 43may readily be computed, and, for the purposes of this description, willbe assumed as being" at the point 44.

The counterweight 40 may be imaginedas divided into two parts, as 40 and40K. The portion 40 is so selected that its center of gravity, as point42, is on a line drawn through the points 43!: and all, and theresultant of the weight at 44- and the weight of the portion 40 is aweight equal to the sum of the two (40 plus 44) and is concentrated atpoint 41. This sum is now ad- 21,093,202 a ll:

ded to the remainder of the counterweight, namely the portion 40*,saidportion 40 having its center of gravity at 41, giving a total weightconcentrated at 41 equalto the sum of 40* plus 44 plus 40 to balance theweight at which includes W plus a certain amount of the link and leverweight as hereinabove described. The balance obtained as thus set forthwill be maintained in all operative positions of the device.

' It is to be noted that in the above exemplary discussion of a methodfor determining the size and location of the counterweight all of theforces are considered as acting in the same plane. Persons skilled inthe art will be able readily to make practical computations for anyparticular application of the invention disclosed. It is thus to beobserved that one counterweight suffices, in the application of myinvention, to the counterbalancing of the weight applied at 25 as wellas the weight of the counterbalance structure,. said counterweight-asawhole being fixed in suchposition that it has an approximately verticalmovement'when the counterbalanced weight is moved vertically, the point41 always moving in a vertical line.

It is to be understood that in practical construction the counterweightmay ex- .tend from one counterbalance lever 33 of l to.

the pair, as shown in Fig. 3, to the other, and that for computationhalf of the weight of the spanmay be considered'the proper portion ofthe weight to be counterbalanced by the two counterbalancing structuresat one end of the-span 20. 'Should it be desired to compute the weightnecessary to be applied on one counterbalance lever alone, one-fourth ofthe weight of the span may be considered the proper portion of theweight so to be counterbalanced, assuming, of course, that the. movablespan is symmetrical constructed so that its center of gravity isequidistant from each of the four points of support. Eachcounterbalancin'g device may, of course, carry a counterweightindependently of any other cooperating counterbalancing device.

In Fig. 4 of the'drawings the ,free end of the connection lever 33 isattached to the span 20 at 25, the counterweight 40' being applied tothe counterbalance lever 34*. This arrangement embodies the samemechanical features as that shown in Fig. 1 and will not require furtherseparate descriptiom.

While I have illustrated and described preferred and modifiedembodiments of these improvements in their application to a lift:-bridge, the invention is not limited to the embodiments shown anddescribed or to'the application herein set forth, as

changes may be made in details of construe in the principle of themechanics employed and within the scope of the invention; and all suchchanges, modifications and adapttations are contemplated by me as fallwithin'the scope'of the appended claims.

I claim:

1. In a counterbalance for a bridge having a vertically movable part,the combination-with such vertically movable part, of a fixed support, aplurality of links having a common pivotal axis mounted on said fixedsupport, a lever pivoted to each of said links, said levers beingpivoted together,

one of said levers being connected operatively to said verticallymovable part, and a counterbalancing weight attached to another of saidlevers and adapted to counterbalance a proper portion of the weight ofsuchoperatively connected to said verticallyf movable part, and acounterweight on one of said levers adapted to counterbalance a properportion of the weight of such vertically movable part.

3. In a bridge, the combination of a vertically movable span, a fixedsupport, a plurality of links pivotally mounted on a common axis on saidfixed support, a plurality of levers pivotally carried by said links,said levers being pivoted together, a counterbalancing weight on one ofsaid levers adapted to counterbalance a proper portion of the weight ofsaid vertically movable span, and a connection between one of said.levers and said span.

4. In a bridge, the combiniition of a vertically movable span, a fixedsupport adjacent to said span, two levers pivoted together and eachlever pivoted to one of two links respectively, said-links beingpivotally mounted on a common axis on said fixed support, a connectionbetween said .associatcd levers and links and said span, and acounterbalancing weight associated with one ofsaidlevers and adapted tocounterbalance a proper portion of the weight of said span.

5. In a bridge, the combination of a ver tically movable span, aplurality of fixed supports adjacent to said span, and a couned toanother of said links, said levers being pivotally connected together,said links and levers forming a parallelogram, a counterbalancin weightrigidly 'attached to said counter alance lever; said connecting leversbeing pivotally connected to said span, said counterbalancing weightbeing adapted to chunterbalanee both the weight of the span to becounterbalanced and the weight of said links and levers in all operativepositions as the span is vertically moved, and means for verticallymoving said span. I

6. In a bridge, the combination of a vertically movable span, a fixedsupport adjacent thereto, a plurality of links and levers pivotedtogether forming a unitary parallelogram structure, two of said linksbeing pivotally mounted with a common axis on said fixed support, thearrangement being such that said unitary structure is adapted to revolvethrough a partial orbit about said fixed support, a counterbalancingweight on one of said levers adapted to counterbalance the. weight ofsaid unitary structure and also a proper portion of the weight of saidspan, and a connection between one of said levers and said span.

7. In a bridge, the combination of a vertically movable span,counterbalancing mechanismf therewith, a fixed support adjacent to saidspan, a pivoton said fixed sup port adapted to carry the weight of theshifting counterbalancing mechanism and the weight of the span to becounterbalanced thereby, said counterbalancing mechanism comprising acounterbalance lever spaced from said pivot in all operative positionsof said lever, means (including a link connectin piece directly betweensaid pivot and said ever) adapted to maintain said lever in such spacedrelation to said pivot that said lever moves bodily through a par tialorbit about said pivot when the span is raised or lowered, said leverhaving a counterbalance weight connected therewith, and meansoperatively connecting saidlever and associated parts to said span, saidcounterbalance weight being adapted to counterbalance the weight of thespan to be counterbalanced by said counter-balancing mechanism.

8. In a bridge and counter-balancing mechanism therewith, thecombination of a vertically movable span, a fixed support adjacent tothe span, a pivot on said fixed support adapted to carry a weightincluding a proper-portion of the total weight of'the span to becounterbalanced, a counterbalance lever, means pivoted on said fixedsupport and operatively connected with said coun terbalanc'e leveradapted to maintain said lever in spaced relation to said pivot in all:o'perative positions of the lever, a single counterweight connectedwith said counterbalance lever, said counterweight being adaptedto'counterbalance both the weight of the counterbalancing device to becoun terbalanced and that portion of the weight of the span as is to becounterbalanced by said counterbalancing device, a connecting elementoperatively connecting the counterbalancing mechanism and said span, thearrangement being such that the center of gravity of the shiftingcounterbalancing elements and of the weight of the span as concentratedat the point of connection be-- tween said connecting element and saidspan is at said pivot in all operative positions of the counterbalancingdevice.

9. In a bridge, the combination of a fixed support, a movable span, acounterbalance lever mounted to rock in spaced relation to said fixedsupport, means connecting said fixed support and said lever, said meansmaintaining said lever in spaced relation to said supportin alloperative positions of the device, means connecting said lever and saidspan, said means having a pivotalconnection with said span, a singlecounterweight rigidly connected with said lever, said weight beingadapted to counterbalance both the.

the lever members of said parallelogram,

and" aco-nnection between the other of said levers and said span, saldcounterweight bemg adapted to counterbalance 1n all operative positionsof the device both the weight of the span to be counterbalanced and theweight of the eounterbalancing links and levers. 1

v 11.111 :1 counterbalance for a bridge, the combination of a movablespan, a fixed support adjacent thereto, two adjacent links and twoadjacent levers all pivotally connected together to form a parallelogramstructure, the common pivot of said adjacent links of said parallelogramstructure being mounted upon said fixed support, onev of said'levers ofsaid parallelogram structure being extended beyond one of the pivotalpoints thereon, and a counterweight on said extension, the other of saidlevers being extended beyond one of the pivotal points thereon, andmeans for connecting said last mentioned extension to said movable span,

jacent to said span, two links mounted to,

said connected links and levers forming a parallelogram structure in alloperative positions of the device, sald parallelogram structure beingadapted to move bodily upon one corner thereof at said first mentionedcommon axis, each of said levers having an extension thereof beyond saidparallelogram structure, a counterbalancing Weight on the extension ofsaid. counter balance lever, the extension of the other lever beingpivotally connected to said span, the arrangement being such that theweight of the span to be counterbalanced by said counterbalancingmechanism as well as the weight of the counterbalancing mechanism to becounterbalanced may be counterbalanced by a single counterweight on oneof said levers.

13. In a bridge, the combination of a vertically movable span andcounterbalancing apparatus therewith, said apparatus compIlSlllg a pairof fixed supports ad acent to each end of, saidspan, counterbalancingmechanism on each of said supports and connected to said span, each ofsaid counterbalancing mechanisms being adapted to counterbalance itsproper portion of the weight of the span as it is raised and lowered,one of said counterbalaneing mechanisms comprising two links pivotallymounted to rock on a common axis on its fixed support, a counterbalancelever pivotally mounted on one of said links, a second lever pivotallyconnected to said span, to the other of said links, and also to .saidcounterbalance lever, said links and levers being connected together andforming a parallelogram structure in'all' operative positions of thedevice, a counterweight connected to said counterbalance lever, saidcounterweight being adapted to counterbalance the Weight of said linksand levers to be counterbalanced and also a proper portion of the weightof said span to be counterbalanced by said counterbalancing apparatus,and means for vertically moving said span.

' CLIFFORD E. PAINE.

Witnesses HENRY M. HUXLEY, M. M; KRIESAND.

